SmogRank / Episodes / Canada
Alberta, Saskatchewan and British Columbia, Canada, September 2023
For 5 days, from 15 to 19 September 2023, 19 cities in Canada had PM2.5 at least twice their usual for the time of year. The worst reading was Grande Prairie, Alberta, Canada: 277.0 µg/m³ on 16 September, about 55× its usual 5.0. Ended 19 September.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 19 in 1 country
Days 5 15 to 19 September 2023
Worst day 16 September 14 cities counted
Furthest above usual 55× Grande Prairie
Day by day
Play 16 September 14 cities at twice their usual or more
Airdrie Calgary Lethbridge Medicine Hat Cranbrook Creston Havre Castlegar Vernon Kelowna Penticton Kamloops Hope Agassiz Chilliwack Abbotsford Lynden Whistler Bellingham Langley Port Coquitlam Coquitlam Anacortes Strawberry Hill Burnaby Squamish North Vancouver Delta Vancouver West Vancouver Richmond Flin Flon Gibsons North Cowichan Duncan Nanaimo Harewood Swift Current Williams Lake Red Deer Prince Albert Sherwood Park Estevan Regina Saskatoon Fort McMurray Fort St. John St. Albert Drayton Valley Edmonton Fort Saskatchewan Grand Centre Quesnel Edson Prince George Grande Prairie 12 Sep 13 14 15 16 17 18 19 20 21 22 Every measured city in the area, coloured by its PM2.5 that day; a dark ring marks a city at twice its usual or more. Bars: cities counted each day, coloured by their median level. Choose a day or press play; without JavaScript, the days link to that day's world ranking.
How it spread
Prince George Prince George, 12 September: 33.4 µg/m³ Prince George, 13 September: 13.7 µg/m³ Prince George, 14 September: 14.9 µg/m³ Prince George, 15 September: 80.8 µg/m³, 12× its usual 6.7 Prince George, 16 September: 144.0 µg/m³, 22× its usual 6.5 Prince George, 17 September: 69.2 µg/m³, 10× its usual 6.7 Prince George, 18 September: 23.2 µg/m³ Prince George, 19 September: 4.9 µg/m³ Prince George, 20 September: 66.1 µg/m³ Prince George, 21 September: 17.9 µg/m³ Prince George, 22 September: 15.8 µg/m³ Estevan Estevan, 12 September: 9.7 µg/m³ Estevan, 13 September: 11.2 µg/m³ Estevan, 14 September: 16.0 µg/m³ Estevan, 15 September: 76.2 µg/m³, 9.4× its usual 8.1 Estevan, 16 September: 43.6 µg/m³, 5.6× its usual 7.8 Estevan, 17 September: 20.9 µg/m³ Estevan, 18 September: 23.5 µg/m³ Estevan, 19 September: 51.9 µg/m³, 6.7× its usual 7.8 Estevan, 20 September: 20.6 µg/m³ Estevan, 21 September: 25.0 µg/m³ Estevan, 22 September: 25.6 µg/m³ Regina Regina, 12 September: 12.1 µg/m³ Regina, 13 September: 14.4 µg/m³ Regina, 14 September: 35.8 µg/m³ Regina, 15 September: 72.0 µg/m³, 11× its usual 6.8 Regina, 16 September: 69.4 µg/m³, 11× its usual 6.6 Regina, 17 September: 26.6 µg/m³ Regina, 18 September: 49.0 µg/m³, 7.4× its usual 6.6 Regina, 19 September: 66.7 µg/m³, 10.0× its usual 6.7 Regina, 20 September: 24.5 µg/m³ Regina, 21 September: 27.7 µg/m³ Regina, 22 September: 31.9 µg/m³ Prince Albert Prince Albert, 12 September: 10.8 µg/m³ Prince Albert, 13 September: 50.1 µg/m³ Prince Albert, 14 September: 26.0 µg/m³ Prince Albert, 15 September: 65.9 µg/m³, 6.7× its usual 9.8 Prince Albert, 16 September: 38.4 µg/m³, 4.0× its usual 9.7 Prince Albert, 17 September: 24.5 µg/m³ Prince Albert, 18 September: 59.1 µg/m³, 6.2× its usual 9.5 Prince Albert, 19 September: 28.2 µg/m³, 3.0× its usual 9.3 Prince Albert, 20 September: 21.2 µg/m³ Prince Albert, 21 September: 23.8 µg/m³ Prince Albert, 22 September: 26.1 µg/m³ Saskatoon Saskatoon, 12 September: 9.3 µg/m³ Saskatoon, 13 September: 36.9 µg/m³ Saskatoon, 14 September: 28.2 µg/m³ Saskatoon, 15 September: 39.8 µg/m³, 5.4× its usual 7.4 Saskatoon, 16 September: 46.6 µg/m³, 6.6× its usual 7.1 Saskatoon, 17 September: 13.0 µg/m³ Saskatoon, 18 September: 75.0 µg/m³, 11× its usual 6.9 Saskatoon, 19 September: 31.5 µg/m³, 4.6× its usual 6.9 Saskatoon, 20 September: 15.8 µg/m³ Saskatoon, 21 September: 23.8 µg/m³ Saskatoon, 22 September: 20.6 µg/m³ Quesnel Quesnel, 12 September: 20.1 µg/m³ Quesnel, 13 September: 6.4 µg/m³ Quesnel, 14 September: 7.3 µg/m³ Quesnel, 15 September: 38.0 µg/m³, 5.1× its usual 7.5 Quesnel, 16 September: 127.0 µg/m³, 17× its usual 7.5 Quesnel, 17 September: 73.8 µg/m³, 9.8× its usual 7.5 Quesnel, 18 September: 3.6 µg/m³ Quesnel, 19 September: 4.8 µg/m³ Quesnel, 20 September: 17.2 µg/m³ Quesnel, 21 September: 17.2 µg/m³ Quesnel, 22 September: 21.6 µg/m³ Fort St. John Fort St. John, 12 September: 144.0 µg/m³ Fort St. John, 13 September: 13.1 µg/m³ Fort St. John, 14 September: 18.4 µg/m³ Fort St. John, 15 September: 31.4 µg/m³, 6.3× its usual 5.0 Fort St. John, 16 September: 24.1 µg/m³ Fort St. John, 17 September: 57.4 µg/m³, 11× its usual 5.0 Fort St. John, 18 September: 10.4 µg/m³ Fort St. John, 19 September: 8.2 µg/m³ Fort St. John, 20 September: 14.0 µg/m³ Fort St. John, 21 September: 18.5 µg/m³ Fort St. John, 22 September: 14.9 µg/m³ Grande Prairie Grande Prairie, 12 September: 35.7 µg/m³ Grande Prairie, 13 September: 28.8 µg/m³ Grande Prairie, 14 September: 64.4 µg/m³ Grande Prairie, 15 September: 26.5 µg/m³, 5.1× its usual 5.2 Grande Prairie, 16 September: 277.0 µg/m³, 55× its usual 5.0 Grande Prairie, 17 September: 207.0 µg/m³, 41× its usual 5.0 Grande Prairie, 18 September: 22.0 µg/m³ Grande Prairie, 19 September: 23.3 µg/m³ Grande Prairie, 20 September: 74.9 µg/m³ Grande Prairie, 21 September: 27.2 µg/m³ Grande Prairie, 22 September: 14.4 µg/m³ Edmonton Edmonton, 12 September: 40.3 µg/m³ Edmonton, 13 September: 32.9 µg/m³ Edmonton, 14 September: 38.3 µg/m³ Edmonton, 15 September: 30.9 µg/m³ Edmonton, 16 September: 98.8 µg/m³, 9.9× its usual 10.0 Edmonton, 17 September: 121.0 µg/m³, 12× its usual 10.0 Edmonton, 18 September: 72.6 µg/m³, 7.3× its usual 9.9 Edmonton, 19 September: 9.6 µg/m³ Edmonton, 20 September: 16.2 µg/m³ Edmonton, 21 September: 17.9 µg/m³ Edmonton, 22 September: 16.9 µg/m³ Drayton Valley Drayton Valley, 12 September: 28.4 µg/m³ Drayton Valley, 13 September: 11.6 µg/m³ Drayton Valley, 14 September: 15.7 µg/m³ Drayton Valley, 15 September: 11.5 µg/m³ Drayton Valley, 16 September: 80.8 µg/m³, 12× its usual 6.8 Drayton Valley, 17 September: 79.6 µg/m³, 12× its usual 6.6 Drayton Valley, 18 September: 21.0 µg/m³ Drayton Valley, 19 September: 2.5 µg/m³ Drayton Valley, 20 September: 7.6 µg/m³ Drayton Valley, 21 September: 8.8 µg/m³ Drayton Valley, 22 September: 12.6 µg/m³ Fort Saskatchewan Fort Saskatchewan, 12 September: 32.0 µg/m³ Fort Saskatchewan, 13 September: 31.1 µg/m³ Fort Saskatchewan, 14 September: 24.7 µg/m³ Fort Saskatchewan, 15 September: 20.9 µg/m³ Fort Saskatchewan, 16 September: 77.1 µg/m³, 10× its usual 7.5 Fort Saskatchewan, 17 September: 100.0 µg/m³, 14× its usual 7.1 Fort Saskatchewan, 18 September: 68.1 µg/m³, 9.6× its usual 7.1 Fort Saskatchewan, 19 September: 8.0 µg/m³ Fort Saskatchewan, 20 September: 12.1 µg/m³ Fort Saskatchewan, 21 September: 14.7 µg/m³ Fort Saskatchewan, 22 September: 14.1 µg/m³ Edson Edson, 12 September: 8.6 µg/m³ Edson, 13 September: 5.0 µg/m³ Edson, 14 September: 10.9 µg/m³ Edson, 15 September: 9.7 µg/m³ Edson, 16 September: 74.3 µg/m³, 14× its usual 5.3 Edson, 17 September: 103.0 µg/m³, 20× its usual 5.2 Edson, 18 September: 17.8 µg/m³ Edson, 19 September: 2.5 µg/m³ Edson, 20 September: 6.4 µg/m³ Edson, 21 September: 11.1 µg/m³ Edson, 22 September: 8.1 µg/m³ St. Albert St. Albert, 12 September: no reading St. Albert, 13 September: 16.6 µg/m³ St. Albert, 14 September: 20.5 µg/m³ St. Albert, 15 September: 13.2 µg/m³ St. Albert, 16 September: 57.7 µg/m³, 8.7× its usual 6.6 St. Albert, 17 September: 78.7 µg/m³, 12× its usual 6.6 St. Albert, 18 September: 44.0 µg/m³, 6.9× its usual 6.4 St. Albert, 19 September: 2.7 µg/m³ St. Albert, 20 September: 6.2 µg/m³ St. Albert, 21 September: 8.7 µg/m³ St. Albert, 22 September: 13.5 µg/m³ Sherwood Park Sherwood Park, 12 September: no reading Sherwood Park, 13 September: 17.3 µg/m³ Sherwood Park, 14 September: 15.7 µg/m³ Sherwood Park, 15 September: 12.8 µg/m³ Sherwood Park, 16 September: 47.3 µg/m³, 6.1× its usual 7.7 Sherwood Park, 17 September: 64.7 µg/m³, 8.5× its usual 7.6 Sherwood Park, 18 September: 38.7 µg/m³, 5.4× its usual 7.2 Sherwood Park, 19 September: 3.4 µg/m³ Sherwood Park, 20 September: 9.0 µg/m³ Sherwood Park, 21 September: 10.3 µg/m³ Sherwood Park, 22 September: 8.9 µg/m³ Williams Lake Williams Lake, 12 September: 3.0 µg/m³ Williams Lake, 13 September: 2.8 µg/m³ Williams Lake, 14 September: 2.9 µg/m³ Williams Lake, 15 September: 10.4 µg/m³ Williams Lake, 16 September: 28.5 µg/m³, 5.7× its usual 3.1 Williams Lake, 17 September: 6.8 µg/m³ Williams Lake, 18 September: 1.7 µg/m³ Williams Lake, 19 September: 2.4 µg/m³ Williams Lake, 20 September: 6.8 µg/m³ Williams Lake, 21 September: 7.7 µg/m³ Williams Lake, 22 September: 7.0 µg/m³ Fort McMurray Fort McMurray, 12 September: 65.8 µg/m³ Fort McMurray, 13 September: 92.5 µg/m³ Fort McMurray, 14 September: 29.0 µg/m³ Fort McMurray, 15 September: 20.4 µg/m³ Fort McMurray, 16 September: 48.4 µg/m³ Fort McMurray, 17 September: 81.5 µg/m³, 10× its usual 8.1 Fort McMurray, 18 September: 83.5 µg/m³, 11× its usual 7.6 Fort McMurray, 19 September: 25.3 µg/m³ Fort McMurray, 20 September: 92.3 µg/m³ Fort McMurray, 21 September: 59.6 µg/m³ Fort McMurray, 22 September: 13.6 µg/m³ Red Deer Red Deer, 12 September: 9.9 µg/m³ Red Deer, 13 September: 11.7 µg/m³ Red Deer, 14 September: 19.0 µg/m³ Red Deer, 15 September: 18.2 µg/m³ Red Deer, 16 September: 17.0 µg/m³ Red Deer, 17 September: 53.1 µg/m³, 6.6× its usual 8.1 Red Deer, 18 September: 50.4 µg/m³, 6.2× its usual 8.1 Red Deer, 19 September: 7.7 µg/m³ Red Deer, 20 September: 9.0 µg/m³ Red Deer, 21 September: 12.1 µg/m³ Red Deer, 22 September: 13.2 µg/m³ Grand Centre Grand Centre, 12 September: 12.7 µg/m³ Grand Centre, 13 September: 28.8 µg/m³ Grand Centre, 14 September: 20.2 µg/m³ Grand Centre, 15 September: 10.4 µg/m³ Grand Centre, 16 September: 13.5 µg/m³ Grand Centre, 17 September: 27.5 µg/m³, 4.8× its usual 5.7 Grand Centre, 18 September: 84.8 µg/m³, 16× its usual 5.4 Grand Centre, 19 September: 14.3 µg/m³ Grand Centre, 20 September: 24.2 µg/m³ Grand Centre, 21 September: 36.7 µg/m³ Grand Centre, 22 September: 20.8 µg/m³ Swift Current Swift Current, 12 September: 8.0 µg/m³ Swift Current, 13 September: 14.0 µg/m³ Swift Current, 14 September: 22.2 µg/m³ Swift Current, 15 September: 10.1 µg/m³ Swift Current, 16 September: 8.3 µg/m³ Swift Current, 17 September: 10.2 µg/m³ Swift Current, 18 September: 26.3 µg/m³, 4.5× its usual 5.8 Swift Current, 19 September: 11.8 µg/m³ Swift Current, 20 September: 7.1 µg/m³ Swift Current, 21 September: 8.3 µg/m³ Swift Current, 22 September: 15.9 µg/m³ 12 Sep 14 16 18 20 22 Every counted city, in the order the episode reached them, 3 days before to 3 after. Each square is a day, coloured by that day's PM2.5; outlined: at twice the city's usual or more. Good 0–50
Moderate 51–100
Sensitive groups 101–150
Unhealthy 151–200
Very unhealthy 201–300
Hazardous 301+
Every city it reached
City Days Highest Usual Above usual
Grande Prairie Alberta, Canada 3 16 September 5.0 55× Prince George British Columbia, Canada 3 16 September 6.5 22× Edson Alberta, Canada 2 17 September 5.2 20× Quesnel British Columbia, Canada 3 16 September 7.5 17× Grand Centre Alberta, Canada 2 18 September 5.4 16× Fort Saskatchewan Alberta, Canada 3 17 September 7.1 14× Edmonton Alberta, Canada 3 17 September 10.0 12× Drayton Valley Alberta, Canada 2 16 September 6.8 12× St. Albert Alberta, Canada 3 17 September 6.6 12× Fort St. John British Columbia, Canada 2 17 September 5.0 12× Fort McMurray Alberta, Canada 2 18 September 7.6 11× Saskatoon Saskatchewan, Canada 4 18 September 6.9 11× Regina Saskatchewan, Canada 4 15 September 6.8 11× Estevan Saskatchewan, Canada 3 15 September 8.1 9.4× Sherwood Park Alberta, Canada 3 17 September 7.6 8.5× Prince Albert Saskatchewan, Canada 4 15 September 9.8 6.7× Red Deer Alberta, Canada 2 17 September 8.1 6.6× Williams Lake British Columbia, Canada 1 16 September 3.1 5.7× Swift Current Saskatchewan, Canada 1 18 September 5.8 4.5×
Daily means in µg/m³, over the days each city counted in this episode. Highest: its highest of those days. Usual: the city's median for the time of year of that day (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that, with a usual under 5 µg/m³ taken as 5.
Against other episodes in Canada
Number 16 of 43 episodes in Canada since our records began, by cities reached.
North-western United States and Canada, August 2023 176 Northern United States and Canada, July 2025 139 North-western United States and Canada, July and August 2026 118 North-western United States and Canada, August and September 2025 94 North-western United States and Canada, July 2024 92 Northern United States and Canada, May 2023 83 Northern United States and Canada, August and September 2023 82 North-western United States and Canada, May 2023 63 North-western Canada and United States, September 2025 57 North-eastern United States and Canada, March 2026 40 North-western Canada and United States, June 2025 28 South-eastern Canada and United States, December 2024 27 Alberta, Saskatchewan and British Columbia, Canada, September 2023 19 Bars: cities reached; colour: the level of the episode's highest daily reading. All 43 .
Use this page SmogRank, Alberta, Saskatchewan and British Columbia, Canada, September 2023: 19 cities with PM2.5 at twice their usual or more, 15 to 19 September 2023, smogrank.com/episodes/2023-09-alberta-saskatchewan-and-british-columbia-canada (accessed 5 October 2026).
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You're welcome to reuse a single chart, image or figure with this citation and a link. Terms .
An episode is a run of days when many cities close to each other (four or more within 350 km on a day, 8 or more in all) each had a daily PM2.5 mean of at least 25 µg/m³ and at least 2 times their usual for that time of year. Found in our own measurements, not picked by hand. How we find episodes . Values are each city's daily mean of its own monitors; causes are the usual kinds for a pattern like this, not a confirmed source.
